Devices and methods for minimally invasive spinal stablization and instrumentation

ABSTRACT

Described herein are devices and methods for fusion of adjacent vertebral bones using distractor platforms for exposure and resection of at least a portion of the facet joint, such as in performance of a TLiF procedure. In one embodiment, the distractor platform contains at least a first receptacle and/or extension adapted to couple to the implanted screw/bone marker and the method includes advancing a threaded segment of a bone fastener assembly into the identified first pedicle of the first vertebral bone, the first bone fastener assembly further comprises a second segment adapted to couple with a distraction platform adapted to concurrently attach onto at least one tissue retention blade and adapted to retain the tissue retention blade in the displaced position. Stabilization of a spinal segment is also provided by advancing a substantially concave orthopedic implant through an opening made in a posterior aspect of a disc space.

CROSS-REFERENCE TO PRIORITY DOCUMENT

This application is a continuation of and claims priority to co-pendingU.S. patent application Ser. No. 13/875,228 filed on May 1, 2013 of thesame title, issuing as U.S. Pat. No. 8,764,806 on Jul. 1, 2014, which isincorporated herein by reference in its entirety, and which is acontinuation of and claims priority to U.S. patent application Ser. No.12/962,534 filed on Dec. 7, 2010 of the same title, which is herebyincorporated by reference in its entirety, and which This applicationclaims priority of co-pending U.S. Provisional Patent Application Ser.No. 61/283,745, entitled “Devices and Methods for Minimally InvasiveSpinal Stabilization and Instrumentation”, filed Dec. 7, 2009. Priorityof the aforementioned filing date is hereby claimed and the disclosureof the provisional patent application is hereby incorporated byreference in its entirety.

BACKGROUND

Disclosed herein are devices, systems and methods of stabilization ofthe bony elements of the skeleton. These devices will permit adjustmentand maintenance of the spatial relationship(s) between neighboringbones. Depending on the specifics of the design, the motion betweenskeletal segments may be immobilized completely or preserved.

Surgical reconstructions of the bony skeleton are common procedures incurrent medical practice. Regardless of the anatomical region or thespecifics of the reconstructive procedure, many surgeons employ animplantable device that can adjust, align and maintain the spatialrelationship(s) between adjacent bones.

Whether from degenerative disease, traumatic disruption, infection orneoplastic invasion, alteration in the anatomical relationships betweenthe spinal vertebras can cause significant pain, deformity anddisability. Spinal disease is a major health problem in theindustrialized world and the surgical treatment of spinal pathology isan evolving discipline. The current surgical treatment of abnormalvertebral motion is the complete immobilization and bony fusion of theinvolved spinal segment. An extensive array of surgical techniques andimplantable devices have been formulated to accomplish this goal.

Vertebral fusion may be accomplished by using an anterior, lateral orposterior approach and each has particular advantages and draw backs.Frequently, circumferential fusion of the unstable level with fixationof both the anterior and posterior aspect of the spine is desired. Thisrequires that patients undergo a combination of the aforementionedapproaches. The anterior or lateral approaches are used to insert thebone graft into the disc space between the adjacent vertebras while theposterior approach is used to place bone screws or similar fastenersthat are used to immobilize the vertebral bodies.

A Trans-foraminal Lumbar Interbody Fusion (TLIF) is known in the art topermit circumferential fusion of the spine through a single surgicalapproach. (The procedure is described in several literature citations,including: Transforaminal Lumbar Interbody Fusion by Alan Moskowitz,Orthop Clin N Am 33 (2002) 359-366. The article is hereby incorporatedby reference in its entirety.)

The procedure requires an oblique approach to the posterior aspect ofthe spine. Unfortunately, an oblique operative corridor is less familiarto surgeons and contains fewer recognizable anatomical landmarks—leadingto a higher rate of intra-operative confusion and loss of directionamong operating surgeons. This difficulty is compounded when theprocedure is performed using minimally invasive or percutaneous surgicaltechnique, wherein the extent of tissue exposure is purposefullyminimized. With the lack of surgical landmarks, the probability ofintra-operative misdirection and the consequent development of surgicalcomplications are necessarily increased.

In the current execution of the trans-foraminallumbar interbody fusion(TLIF), the surgeon makes a skin incision posterior to the spinal levelthat is to be fused, develops a dissection corridor through the softtissues adjacent to the spine and arrives at a facet joint of the spinallevel to be fused. The facet joint is then at least partially removed inorder to provide access to the posterior surface of the disc space whichis positioned immediately anterior to the facet joint. The disc space isentered, prepared to accept fusion (preparation of the disc space is awell known procedure in the art and will not be described in detailhere) and then implanted with the desired implant and material. Afterdisc space implantation, the surgeon frequently, but not necessarily,desires to add supplemental orthopedic instrumentation to rigidly fixatethe operative level while the bony fusion matures. Most commonly, thesupplemental fixation involves placement of bone anchors (usuallyscrews) that are interconnected with an interconnecting members (usuallyone or more rods).

In the current execution of the trans-foraminal lumbar interbody fusion(TLIF), it is the development of a dissection corridor through the softtissues from the skin incision to the facet joint that is most likely tocreate disorientation and confusion. The surgeon often arrives at a bonyprominence of the underlying vertebral bones but may be unclear as towhich segment of the bone it is or the precise orientation of the softtissue corridor relative to the vertebral bones that must be fused. Thelack of reliable surgical landmarks during development of the obliquesoft tissue corridor adds to the uncertainly and this difficulty iscompounded when the procedure is performed using minimally invasive orpercutaneous surgical technique, wherein the extent of tissue exposureis purposefully minimized.

SUMMARY

Provided herein are devices and methods for the safe and reproducibleplacement of an orthopedic implant into the disc space of a desiredspinal segment. The disclosed procedure is especially well adapted forperforming minimally invasive or percutaneous trans-foraminal lumbarinterbody fusion (TLIF) procedures. However, while described for aposterior fusion technique of the lumbar spine, it is neverthelessunderstood that the devices and methods described herein may be usedwith any other applicable surgical approach to any applicable spinallevel. Further, the devices and method may be used to implant non-fusionimplants (such as artificial discs, replacement nucleus pulposis, andthe like) into a targeted disc space.

The disclosed devices and methods include identifying and targeting aportion of a vertebral bone adjacent to the disc space to be implantedin the initial operative steps. A marker is advanced into the identifiedbony segment and the marker is used as a reference to orient thesurgical corridor and to correctly identify the segments of bone anddisc to be removed and/or manipulated. In a preferred embodiment that isillustrated in a TLIF procedure, the pedicle portion of the vertebralbone is the targeted segment of bone that is identified and marked.Preferably the pedicle is marked with a bone screw that is anchored intoit and the pedicle and screw are then used to define and orient thesubsequent operative steps. In another embodiment that is illustrated inthe performance of a TLIF procedure, the facet joint is the targetedsegment that is identified and marker. Preferably, the facet joint ismarked with a bone screw that is anchored into it and the screw is thenused to define and orient the subsequent operative steps.

Disclosed is a method wherein a segment of bone of at least one vertebrathat borders the disc space to be implanted is identifiedintra-operatively by imaging techniques (X-rays, CT, MRI and the like).A marker, such as a bone screw, is placed into the identified bonesegment and the attached marker forms a readily identifiable surgicalland mark for the surgeon during formation of the surgical corridor.When illustrated in the performance of a TLIF procedure, the marker ispreferably positioned into the pedicle or facet portion of the vertebralbone. The marker is coupled to bone prior to resection of the facetjoint. The marker is used to define the exposure and orient the surgeonduring the subsequent bony manipulation.

In the preferred embodiment, it is the pedicle portion of the vertebralbone that is localized and marked. The devices and methods describedherein are illustrated in the performance of a minimally invasivetrans-foraminal lumbar interbody fusion (TLIF) procedure, wherein a bonescrew is placed into the identified pedicle and the bone screw forms areadily identifiable surgical land mark for the surgeon during formationof the surgical corridor to the facet joint and its subsequent removal.

Disclosed are distractor platforms and methods of use for the exposureand resection of at least a portion of the facet joint in performance ofa TLIF procedure. In an embodiment, the distractor platform contains atleast a first receptacle and/or extension that are adapted to couple tothe implanted screw/bone marker. Preferably, the distractor platformalso contains at least one retractor blade that is adapted to retractand retain the soft tissues that rest posterior to the facet joint so asto expose the posterior aspect of the joint. The tissue retractor blademay be reversibly detachable from the distractor platform and,preferably, the distance from tissue-retracting blade tip to thedistractor platform may be varied so that the distractor blade is, ineffect, of variable in length.

Provided herein are instruments and methods for the unambiguousintroduction of surgical landmarks and corridors for placement of anorthopedic implant into the disc space of a spinal segment. Describedherein are instruments and methods for placement of an orthopedicimplant into the disc space of spinal segment using a trans-foraminallumbar interbody fusion (TLIF) procedure, wherein the TLIF procedure ispreferably performed in a minimally invasive or percutaneous manner.While illustrated in the TLIF approach, it is understood that theillustrated embodiments are not restrictive and the instruments andmethods may be used with any other applicable surgical approach and atany applicable spinal level.

In one aspect provided is a method for fusion of a first vertebral boneand a second adjacent vertebral bone of a subject. The method includesidentifying a first pedicle of the first vertebral bone on radiographicimaging; identifying the second adjacent vertebral bone on radiographicimaging and a first facet joint. The first facet joint forms anarticulation between the first vertebral bone and the second adjacentvertebral bone. The first facet joint resides on the same side of thevertebral midline as the identified first pedicle of the first vertebralbone. The method also includes advancing a first threaded segment of afirst bone fastener assembly into the identified first pedicle of thefirst vertebral bone. The first bone fastener assembly further includesa second segment that is adapted to couple with a distraction platform.The method also includes coupling the distraction platform with thesecond segment of the first bone fastener assembly. The distractionplatform is adapted to concurrently attach onto at least one tissueretention blade. The method further includes positioning the tissueretention blade in proximity to the first bone fastener assembly that isanchored to the pedicle of the first vertebral bone; exposing the firstfacet joint by applying a force to displace the tissue retention bladeaway from the first bone fastener assembly and towards the vertebralmidline. The distraction platform is adapted to retain the tissueretention blade in the displaced position. The method also includesremoving at least a segment of the first facet joint and exposing aposterior surface of an intervertebral disc space. The exposed discspace is positioned between the first and second vertebral bones. Atleast a portion of exposed disc surface is immediately anterior to theremoved portion of the first facet joint. The method also includesentering the posterior aspect of the disc space through atrans-foraminal corridor and removing the distraction platform. Theentry point of the posterior disc is at least partially in between thenerve root that exits the spinal canal beneath the pedicle of thesuperior vertebral bone and the pedicle of the inferior vertebral bone;positioning an implant into the disc space. The implant can bear atleast some of the load transmitted across the disc space and maintainthe superior and inferior vertebral bones separated by a desireddistance.

In another aspect, there is disclosed a method for the fusion of a firstvertebral bone and a second adjacent vertebral bone of a subject. Themethod includes identifying the first vertebral bone on radiographicimaging and a first facet joint, wherein the first facet joint forms anarticulation between the first and second adjacent vertebral bones;advancing a first threaded segment of a first bone fastener into theidentified first facet joint under radiographic guidance, wherein thebone fastener is threadedly anchored onto the first facet joint; usingthe anchored first bone fastener to guide and position a retractionplatform; advancing a distraction platform over the anchored first bonefastener and onto the facet joint, wherein the distraction platform iscoupled to at least two tissue retention extensions; detaching the firstbone fastener from the facet joint in order to form a corridor betweenthe tissue retention extensions of the distraction platform, wherein thecorridor permits direct access to the posterior aspect of the firstfacet joint; identifying visually the first facet joint at the distalend of the corridor between the tissue retention extensions of thedistraction platform; removing at least a segment of the first facetjoint and exposing a posterior surface of an intervertebral disc space,wherein the exposed disc space is positioned between the first andsecond vertebral bones, wherein at least a portion of exposed discsurface is immediately anterior to the removed portion of the firstfacet joint; entering the posterior aspect of the disc space through atrans-foraminal corridor, wherein the entry point of the posterior discis at least partially in between the nerve root that exits the spinalcanal beneath the pedicle of the superior vertebral bone and the pedicleof the inferior vertebral bone; positioning an implant into the discspace, wherein the implant can bear at least some of the loadtransmitted across the disc space and maintain the superior and inferiorvertebral bones separated by a desired distance; and removing thedistraction platform.

In another aspect, an orthopedic implant is disclosed. In oneembodiment, the implant comprises a curvilinear body member comprisingat least a first ipsilateral side surface and an opposing contra-lateralside surface. The curvilinear body is configured to extend along acurvilinear trajectory having a center of rotation positionedipsilateral to the first ipsilateral side surface. The curvilinear shapeof the body member is such that the first ipsilateral side surface issubstantially concave relative to the center of rotation. Thecurvilinear body is configured to be advanced into an intervertebraldisc space of a subject via rotation thereof about a circular trajectorycentered at the center of rotation.

Other features and advantages should be apparent from the followingdescription of various embodiments, which illustrate, by way of example,the principles of the disclosed instruments and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C show diagrammatic representations of a spinal vertebral bonein multiple views.

FIGS. 2A and 2B illustrate a functional spinal unit (FSU), whichincludes two adjacent vertebrae and the intervertebral disc betweenthem.

FIG. 3 shows a schematic representation of the posterior aspect of apatient who is positioned prone.

FIG. 4 illustrates a cross sectional view of the torso at the level of atargeted disc space in the lumbar spine.

FIGS. 5A-B show representative bone screw assembly and coupling devices.

FIG. 6 shows perspective views of bone fastener.

FIG. 7 shows a close-up section view of the fastener of FIG. 6.

FIGS. 8 and 9 show section views through the device assembly of FIG. 5B.

FIG. 10 shows schematically at least one wire advanced partially intothe underlying pedicle of at least one vertebral bone.

FIG. 11 shows a step in the advancement of fastener into the bone.

FIG. 12 shows a step in the advancement of fastener into the bone.

FIG. 13 shows a step in the advancement of fastener into the bone.

FIG. 14 shows an embodiment of a distraction platform.

FIGS. 15A-15C show various views of the platform.

FIG. 16 show various view of the platform.

FIG. 17 shows an exploded view of the platform.

FIGS. 18 and 19 show cross section views of the platform.

FIGS. 20-22 show close-up views of the proximal end of removable tissuedistraction arm.

FIGS. 23-24 show distraction arms positioned within the incision betweeneach of the fastener coupler members.

FIG. 25A-25D show various perspectives of the working corridor.

FIG. 26 shows an embodiment of an instrument adapted to perform both thedrill and rongeur function.

FIG. 27 shows another view of the instrument.

FIGS. 28A-28B show exploded views of the instrument.

FIGS. 29A-29C show various section views of the instrument.

FIG. 30 shows a section view of the instrument.

FIG. 31 shows an instrument positioned to be advanced through theworking corridor.

FIG. 32 shows the instrument fully advanced onto the facet joint.

FIG. 33 shows the facet joint positioned between each foot and distalaspect of member of instrument.

FIG. 34 shows the bone defect formed by instrument with the instrumentpartially removed.

FIG. 35 shows schematic view of the dural sac and contained nerveelement decompressed on the posterior and lateral aspects.

FIGS. 36A-36B show an embodiment of a disc implant.

FIG. 37 shows an implant having at least one cavity that permitscommunication from one side of the implant body to the other.

FIGS. 38A-38B show implant positioned at the defect place din theposterior aspect of the annulus fibrosis of the disc space during discpreparation.

FIG. 39 shows bone graft material placed into the disc space adjacentthe implant.

FIGS. 40A-40B show additional embodiments of implant positioning.

FIGS. 41A-41B show schematic sequence of inter-connecting member used tointerconnect fasteners.

FIGS. 42A-42B show an embodiment of a spinous process device beingimplanted.

FIGS. 43A-43C show an example of a device adapted to perform the method.

FIGS. 44A-44B show steps in the assembly onto the distractor platform.

FIGS. 45A-45B show schematically the housing members attached to thebone screws.

FIG. 45C is a flow diagram summarizing the disclosed methods.

FIGS. 46A-46B show embodiment of a screw member.

FIGS. 47A-47B show another embodiment of threaded screw member used toanchor distraction platform to pedicle portion of vertebral bone.

FIGS. 48A-48C show a retractor platform.

FIG. 49 shows a retractor used to retract the muscle segment mediallytowards the spinous process.

FIG. 50 shows another embodiment of a retractor.

FIGS. 51A-51C show placement of guide wire directly into facet jointspace between the IAP of the superior vertebral bone and SAP of theinterior vertebral bone.

FIGS. 52A-52B show cylindrical tubes of progressively greater diametersequentially passed over member to dilate surrounding soft tissue andadvancement of retractor platform . . . .

FIGS. 53A-53B show tube removed leaving a working corridor within thecentral aspect of the semi-cylindrical retractor blades.

FIG. 54 illustrates a schematic view down the working corridor.

FIG. 55 illustrates an alternative embodiment of the retractor.

DETAILED DESCRIPTION

In order to promote an understanding of the principals of thedisclosure, reference is made to the drawings and the embodimentsillustrated therein. Nevertheless, it will be understood that thedrawings are illustrative and no limitation of the scope of theinvention is thereby intended. Any such alterations and furthermodifications in the illustrated embodiments, and any such furtherapplications of the principles of the invention as illustrated hereinare contemplated as would normally occur to one of ordinary skill in theart.

FIG. 1 shows a diagrammatic representation of a spinal vertebral bone802 in multiple views. For clarity of illustration, the vertebral boneof FIG. 1 and those of other illustrations presented in this applicationare represented schematically and those skilled in the art willappreciate that actual vertebral bodies may include anatomical detailsthat are not shown in these figures. Further, it is understood that thevertebral bones at a given level of the spinal column of a human oranimal subject will contain anatomical features that may not be presentat other levels of the same spinal column. The illustrated vertebralbones are intended to generically represent vertebral bones at anyspinal level without limitation. Thus, the disclosed devices and methodsmay be applied at any applicable spinal level.

Vertebral bone 802 contains an anteriorly-placed vertebral body 804, acentrally placed spinal canal and 806 and posteriorly-placed lamina 808.The pedicle (810) segments of vertebral bone 802 form the lateral aspectof the spinal canal and connect the laminas 808 to the vertebral body804. The spinal canal contains neural structures such as the spinal cordand/or nerves. A midline protrusion termed the spinous process (SP)extends posteriorly from the medial aspect of laminas 808. A protrusionextends laterally from each side of the posterior aspect of thevertebral bone and is termed the transverse process (TP). A righttransverse process (RTP) extends to the right and a left transverseprocess (LTP) extends to the left. A superior protrusion extendssuperiorly above the lamina on each side of the vertebral midline and istermed the superior articulating process (SAP). An inferior protrusionextends inferiorly below the lamina on each side of the vertebralmidline and is termed the inferior articulating process (IAP). Note thatthe posterior aspect of the pedicle can be accessed at an indentation811 in the vertebral bone between the lateral aspect of the SAP and themedial aspect of the transverse process (TP). In surgery, it is commonpractice to anchor a bone fastener into the pedicle portion of avertebral bone by inserting the fastener through indentation 811 andinto the underlying pedicle.

FIGS. 2A and 2B illustrate a functional spinal unit (FSU), whichincludes two adjacent vertebrae and the intervertebral disc betweenthem. The intervertebral disc resides between the inferior surface ofthe upper vertebral body and the superior surface of the lower vertebralbody. (Note that a space is shown in FIGS. 2A and 2B whereintervertebral disc would reside.) FIG. 2A shows the posterior surfaceof the adjacent vertebrae and the articulations between them while FIG.2B shows an oblique view. Note that the FSU contains a three jointcomplex between the two vertebral bones, with the intervertebral disccomprising the anterior joint. The posterior joints include a facetjoint 814 on each side of the midline, wherein the facet joint containsthe articulation between the IAP of the superior vertebral bone and theSAP of the inferior bone.

The preceding illustrations and definitions of anatomical structures areknown to those of ordinary skill in the art. They are described in moredetail in Atlas of Human Anatomy, by Frank Netter, third edition, IconLearning Systems, Teterboro, N.J. The text is hereby incorporated byreference in its entirety.

Illustrated are methods and devices that permit a surgeon to access theanterior column of the spine from a posterior skin incision through atransforaminal surgical approach. The “anterior column” is used here todesignate that portion of the vertebral body and/or FSU that is situatedanterior to the posterior longitudinal ligament (PLL)—and may includethe PLL. Thus, its use in this application encompasses both the anteriorand middle column of Denis. (See The three column spine and itssignificance in the classification of acute thoracolumbar spinalinjuries. By Denis, F. Spine 1983 November-December; 8(8):817-31. Thearticle is incorporated by reference in its entirety.)

It is a purpose of the present invention to provide instruments andmethods for the unambiguous introduction of surgical landmarks andcorridors for placement of an orthopedic implant into the disc space ofa spinal segment. It is a purpose of the present invention tospecifically illustrate the instruments and methods for placement of anorthopedic implant into the disc space of spinal segment using atrans-foraminal lumbar interbody fusion (TLIF) procedure, wherein theTLIF procedure is preferably performed in a minimally invasive orpercutaneous manner. While illustrated in the TLIF approach, it isunderstood that the illustrated embodiments are not restrictive and theinstruments and methods may be applied at other spinal segments and tomethods of implant placement other than TLIF.

For a functional spinal unit (FSU) that has been targeted for placementof an orthopedic implant into the intervening disc space, thetrans-foraminal lumbar interbody fusion (TLIF) procedure requiresremoval of at least a portion of the IAP and SAP of a facet joint 814that is immediately posterior to the disc space to be implanted. Thefacet joint removal may be performed on one side of the vertebralmidline, the opposite side of the vertebral midline or on both sides ofthe vertebral midline. In the existing art, a TLIF procedure is startedwith development of an oblique soft tissue corridor from the skinincision site (which is posterior to the spine) to the facet joint thatmust be removed. Unfortunately, the soft tissue corridor lacks adequatesurgical landmarks and its development can cause intra-operativeconfusion, misdirection and deviation into unintended structures. Thisdifficulty is compounded when the procedure is performed using minimallyinvasive or percutaneous surgical technique.

It is a goal of the current invention to obviate any intra-operativeconfusion by placing bone markers and/or fasteners in at least oneprescribed location of the vertebral bones of the targeted FSU. In apreferred embodiment, the pedicle portion of the upper and/or lowervertebral bones that border the disc space targeted for implantation areidentified and localized on imaging (such as X-rays, CT, MRI and thelike). Bone screws and/or other fasteners are then advanced in apercutaneous manner and under image guidance (such as X-rays, CT, MRIand the like) into the pedicle portion of the localized vertebraethrough small skin incisions. Alternatively, a small posterior skinincision can be made overlying the posterior aspect of the disc spacetargeted for implantation. The bone screws and/or fasteners can then beadvanced through the small incision, in a minimally invasive way, ontothe bone insertion region 811 and into the underlying the pedicle. Inanother embodiment, the bone fasteners may be placed at the boneinsertion site 811 with conventional surgical technique and a largerskin incision. The bone screws and/or fasteners are then used to guidethe formation of the surgical corridor to the facet joint.

Placement of the bone fasteners before resection of the facet jointdiffers from the method of current art, wherein the facet joint isaccessed/resected and an implant is positioned into the disc spacewithout prior placement of the bone screws and/or fasteners. That is, inthe current invention, bone markers are positioned to define thesurgical corridor without prior resection of facet joint. In contrast,the current art does not use fasteners to define the surgical corridorto the facet joint nor are they used to guide implant placement.

After bone screw and/or fastener (hereinafter the terms are usedinterchangeably) placement, a distraction platform is used to coupleand/or attach onto at least one of the hone screw assemblies. In apreferred embodiment, the distraction platform has at least oneadditional distraction arm that is adapted to retract soft tissues(skin, fat, muscle, etc). In specific, the distraction platform iscoupled to each of the bone screws that have been advanced into thepedicle of the superior and inferior vertebral bones of the targetedFSU. Another arm member that is attached to the distraction platform isused to retract medially the soft tissues between the pedicle bonescrews and the spinous process of the vertebrae of the targeted FSU. Inthis way, the facet joint 814 that lies immediately medial and betweenthe two implanted pedicle bone screws is exposed. Using the bone screwsas a coupling point for the distractor platform permits the pedicles andthe anchored screws to be used as a surgical landmark in development ofsoft tissue corridor to the targeted facet joint. Use of another armmember that is coupled to the distraction platform to retract the softtissues medially insures that the facet joint is readily andreproducibly exposed. It also obviates the possibility ofintra-operative confusion by the surgeon.

The soft tissue retractor arm of the distraction is preferably, but notnecessarily, removable. That is, the soft tissue retraction arm can becompletely de-coupled and removed from the distraction platform. Thisprovides maximal degree of versatility for the surgeon. After exposureof the facet joint 814 that is ipsilateral to the implanted bone screws,at least a portion of that facet joint is then removed. This ispreferably, but not necessarily, performed by at least a combination ofdrill/burr removal and rongeur cutting of the bone so as to form acorridor within the facet joint that permits direct access of thesegment of the disc space that is anterior to the removed joint. In anembodiment, the combination drilling and cutting of the facet joint maybe performed by a single instrument. For example, the instrument may beadapted to permit bone removal by advancing a drill or burr through acentral port of the instrument. The instrument may be further adapted tocut bone with sharpened edges—as would a bone rongeur.

After removal of the facet bone, the posterior disc space is accessedthrough a transforaminal corridor. The trans-foraminal corridor extendsin the superior-inferior direction for a distance D1. Distance D1extends from the inferior aspect of the nerve root that exits the spinalcanal beneath the pedicle of the superior vertebral bone and thesuperior aspect of the pedicle of the inferior vertebral bone of thetargeted FSU. The trans-foraminal corridor is bordered medially by thelateral aspect of the nerve root that exits the spinal canal beneath thepedicle of the inferior vertebral bone of the targeted FSU. A segment ofthe posterior aspect of the disc space that is exposed after facetresection is positioned immediately anterior to the trans-foraminalcorridor. While described for completeness, the trans-foraminal corridoris known to those of ordinary skill in the art and may containanatomical features that are not recounted here.

The posterior aspect of the disc space that is immediately anterior tothe trans-foraminal corridor is entered by creation of a defect in theAnnulus Fibrosis. At least partial removal of the disc material isperformed and the bony endplate of each of the inferior surface of thesuperior vertebral bone and superior surface of the inferior vertebralbone are striped of cartilage material and then decorticated. Bone graftor bone graft substitute (hereafter collectively referred to as boneforming material) is then implanted into the evacuated disc space.Preferably, but not necessarily, an implant is concurrently implantedinto the disc space that can bear at least some of the load transmittedacross the disc space and maintain the superior and inferior vertebralbones separated by a desired distance. In an embodiment, the implant maybe solid or it may contain a cavity adapted to house bone graftmaterial, wherein the graft material is adapted to fuse with one or bothof the vertebral bones.

After advancement of the implant into the targeted disc space, thedistraction platform is removed. An inter-connecting member that ispreferably, but not necessarily, a rod, is used to interconnect each ofthe superior and inferior bone fasteners. A locking element of each bonefastener is then deployed so that each bone fastener is rigidly attachedto the interconnecting member. In this way, the fasteners andinterconnecting rod member will rigidly interconnect and immobilize thesuperior and inferior vertebral bones that abut the implanted discspace. Additional immobilization may be produced by the implantation offasteners/interconnecting member into the contra-lateral vertebralpedicles (i.e., on the contra-lateral side of the vertebral midline). Aspinous process fastener that is adapted to rigidly affix to the spinousprocess of each of the superior and inferior vertebral bones and rigidlyimmobilize the FSU may be alternatively used instead of implantation ofthe contra-lateral pedicle bone screws and interconnecting rod. (spinousprocess fixation plates and fasteners are known in the art. Amongothers, U.S. Pat. Nos. 6,582,433, 7,048,736 and US patent applicationpublication numbers US 2007/0270840 and US 2008/0183211 all disclosespinous process fixation implants that may be applicable. Each of thesepatents/applications is hereby incorporated by reference in itsentirety.)

The preferred embodiment is now described in detail and reference ismade to the accompanying drawings. While the disclosed devices may bepositioned in an appropriate spinal level/segment using any appropriatesurgical method and/or surgical corridor, the following disclosureillustrates implant placement into a disc space of a functional spinalunit (FSU) using a posterior skin incision (posterior to spine) and atransforaminal lumbar interbody fusion (TLIF) technique.

In preparation for the minimally invasive placement of the implant intoa targeted spinal level, the patient is preferably, but not necessarily,placed in a prone position or in a lateral decubitus position. The levelof the spine that is to be implanted is localized by imaging techniques(X-rays, CT, MRI and the like) in at least one plane. After thecustomary sterile preparation of the operative site, the surgeonlocalizes the incision points on the skin that are substantially lateralto vertebral midline and overlying the approximate spinal segment thatwill be implanted. FIG. 3 shows a schematic representation of theposterior aspect of a patient who is positioned prone. The skinoverlying the back is shown. Lines Y illustrate a region that isapproximately lateral to the midline and medial to the lateral extent ofthe transverse processes of the spinal column. Assuming that the spinaldisc space to be accessed is skin line Z, the surgeon will access skinregion X₁ that approximately overlies indentation 811 of the superiorvertebral bone and skin region X₂ that approximately overliesindentation 811 of the inferior vertebral bone of the FSU that containsthe targeted disc space. However, it is understood that one or more skinincisions of any sufficient length may be alternatively used.

Bone screws are placed into the pedicle portion of each of the superiorand inferior vertebral bones by penetrating the bony surface atapproximately indentation 811. In the preferred embodiment, the bonescrew placement is performed in a percutaneous manner and under imageguidance (such as X-ray, CT or MRI guidance and the like).Alternatively, the bone fasteners may be placed using a larger incisionand minimally invasive surgery or full open (conventional) surgicaltechnique. In general, each fastener follows an oblique corridor throughthe soft tissues between the skin entry site (wherein the skin entrysite is posterior to the spine) and the bone entry point of indentation811. An approximation of the soft tissue corridor K taken by thefasteners is shown in FIG. 4. FIG. 4 illustrates a cross sectional viewof the torso at the level of a targeted disc space in the lumbar spine.For clarity of illustration, the contents are represented schematicallyand those skilled in the art will appreciate that an actual crosssection of the human torso may include anatomical details not shown inFIG. 4.

FIGS. 5 a and b show a representative bone screw assembly 105 andcoupling device 125 and 130. FIG. 6 shows perspective views of bonefastener 105 while FIG. 7 shows a close-up section view of fastener 105.The bone fastener and coupling instruments are shown in additionaldetail in FIGS. 8 & 9. However, it should be appreciated that theseembodiments are illustrative and there is known in the art many bonefasteners and couplers that may be alternatively used in the methoddisclosed in this application. (For example, U.S. RE37665, U.S. Pat. No.6,248,105, U.S. Pat. No. 6,371,957, U.S. Pat. No. 6,565,565 alldiscloses at least one bone screw assembly that may be used toaccomplish the present method. Each citation is hereby incorporated byreference in its entirety.)

Assembly 105 contains a threaded bone screw 107 with threaded shaft 1072and a spherical head 1074. An internal bore 1076 extends throughout theinternal aspect of the screw 107—extending from top of head 1074 to thetip of shaft 1072. The internal bore has a threaded portion 1078. Ahex-shaped receptacle 1079 resides within head 1074. Receptacle 1079 isadapted to accept a screw driver (such as with a hex-shaped tip, or thelike). wherein the driver can deliver a rotational force to screw 107and drive the threaded shaft into bone.

An outer housing 110 has an internal seat 1102 that is adapt to seathead 1074 of screw 107. Housing 110 has an additional seat 1104 that isadapted to accept an inter-connecting member, such as a rod. Threads1106 are adapted to compliment and accept threaded locking nut 116. Apusher member 114 rests between the two seat portions 1104 and 1102 ofhousing 110 and transmits the downward force of the locking nut 116 ontohead 1074 (when an interconnecting rod is positioned between the lockingnut and pusher member 114).

In use, an interconnecting member, such as a rod, is positioned withinseat 1104 of housing 110. The housing 110 and screw 107 are moved intothe desired relative spatial orientation. Locking nut 116 is positionedabove the seated interconnecting member and then threadedly advancedrelative to threads 1106 of housing 110. As locking nut 116 is advanced,the interconnecting rod member is forced onto pusher member 114. Thepusher 116 is forced downward onto head 1074 of screw 1074 and trappingthe head between the pusher 116 and seat 1102. In this way, fulladvancement of locking nut 116 produces rigid immobilization of theinterconnecting member, the housing 110 and the screw 107 relative toone another. (It should be appreciated that screw assembly 105 is anexample of bone screw assembly that may be used. It is understood thatother bone screw assemblies may be alternatively used. Multiple suchscrew assemblies are known in the art. For example, U.S. RE37665, U.S.Pat. No. 6,248,105, U.S. Pat. No. 6,371,957, U.S. Pat. No. 6,565,565,U.S. Pat. No. 6,641,586, U.S. Pat. No. 7,704,271 all disclose at leastone bone screw assembly that may be used to accomplish the presentmethod. Each citation is hereby incorporated by reference in itsentirety.)

As shown in FIG. 5, the assembly 105 can be coupled to coupler member125 and 130. FIG. 5 a shows the devices in an exploded state while FIG.5 b illustrates the assembled state. Outer member 125 has threaded end1252 that is adapted to threadedly engage threads 1106 of housing 110.Member 125 has an elongated body with a central bore 1254 that extendsthere through from the top to the bottom surface of member 125. Centralbore 1254 is adapted to accept member 130 within. At the top aspect ofmember 125, a hex-shaped segment 1258 is present. The segment 1258 isadapted to accept a hex-shaped driver (driver not shown) on the outeraspect of the member 125, wherein the driver, when engaged, is adaptedto apply a rotational force to member 125.

Internal member 130 has an elongated body with a threaded segment 1302.Internal member 130 has a central bore 1304 that extends there throughfrom the top to the bottom surface of member 130. A “T” shapedprotrusion 1305 has a hex-shaped protrusion 1306 beneath it, whereinhex-shaped protrusion 1306 is adapted to snuggly rest within hex-shapedcut out 1079 of screw 107 such that rotation of member 130 producesrotation of screw 107. Further ‘T’ shaped protrusion 1305 is adapted torest within seat 1104 of housing 110. An additional hex-shapedprotrusion 1308 is located at the top of member 130

FIGS. 8 and 9 show section views through the device assembly of FIG. 5b. FIG. 8 shows a section view that is perpendicular to the “T” shapedprotrusion 1305 of member 130. FIG. 9 illustrates a section view that isparallel to the “T” shaped protrusion 1305 of member 130. In FIGS. 8 and9, member 130 is shown within bore 1254 of member 125. Protrusion 1306rests within cut-out 1079, and aligns the long axis of screw 107 withthat of housing 110, member 130 and member 125. Threads 1252 are driveninto complimentary threads 1106 of housing 110 so that member 125 isthreadedly locked to housing 110. In this way, member 110,107,130 and125 are aligned and rigidly coupled to one another. Further, theapplication of a rotational force to hex-shaped protrusion 1308 (atopmember 130), such as with a hex driver, caused rotation of the completeassembly and permits the advancement of threaded screw 107 into bone,Note that in the rigid assembly of FIG. 5 b, bore 1304 of member 130 isaligned with bore 1076 of screw 107, thereby permitting passage of aguide needle from one end of the assembly through each of bore 1304 andbore 1076 and out the other end of the assembly.

An embodiment of the method of device use is now disclosed, The methodillustration assumes that the L4 and L5 bones are to be fused and theL4/5 disc space is the target for implant placement. However, it isunderstood that the method may be alternatively used at any applicablespinal level. Under imaging guidance (X-ray, CT, MRI and the like), eachof two guide wires 102 (substantially similar to elongated needles) ispercutaneously passed through the skin (at or about skin region X₁ andX₂, and advanced to indentation 811 of each of the L4 and L5 vertebralbones. Each wire 102 preferably contains a threaded distal end with asharpened tip. At least one wire 102 is then advanced (or threaded) atleast partially into the underlying pedicle of at least one vertebralbone. This is schematically shown in FIG. 10 wherein the skin isschematically shown and labeled skin S. Those skilled in the art willappreciate that actual vertebral bodies may include anatomical detailsthat are not shown in FIG. 10.

The skin entry site of and underlying soft tissue surrounding each wireis enlarged in preparation for bone screw placement. This can beperformed using any applicable method but. in the preferred embodiment,serial cylindrical tubes of enlarging diameter are sequentially passedover the guide wire 102. This method of sequential tube dilatation oftissues over a guide wire is well known to those of ordinary skill inthe art and will not be further detailed or illustrated. An assembly ofbone fastener 105 and couplers 125/130 are assembled as shown in FIG. 5b and then advanced over a guide wire 102, wherein guide wire 102extends through bores 1304 and 1076 of the assembly. The assembly isadvanced until the threaded shank of screw 107 engages the vertebralbone at or about indentation 811. With rotation of protrusion 1308(driver not shown) the bone screw is threadedly advanced into thepedicle portion of each vertebral bone. Preferably, the bone screw isadvanced into the pedicle under radiographic visualization.

In actual use, a hole in the bone may need to be pre-formed with a tapinstrument prior to screw placement. Further, the advancement ofinstruments (such as a tap or the bone screw) is preferably performedwith the screw electrically connected to an electromyography (EMG)machine to minimize the possibility of nerve injury. (The technique isknown in the art and is described in 1) Intraoperative electromyographyduring thoracolumbar spinal surgery. By Holland, N R. Spine 1998 Sep. 1:23(17): 1915-22. and 2) Improving accuracy and reducing radiationexposure in minimally invasive lumbar interbody fusion. By Wood M J,Mannion R J. J Neurosurg Spine. 2010 May; 12(5): 533-9. Each article ishereby incorporated by reference in its entirety.)

The sequence is shown in FIGS. 11 and 12. After the fasteners are fullyadvanced into the bone, the guide wires 102 are removed—leaving theimplanted fasteners and couplers as shown in FIG. 13. (An alternativemethod is further contemplated wherein a guide wire is not employed toguide the bone screw assembly. In this embodiment, a larger diametertube is forcibly advanced through the skin and the soft tissue untilindentation 811 of a targeted vertebral bone is reached. A cannula isremoved from within an internal bore of the tube and bone screw assemblyis advanced to indentation 811 through the internal bore of the tube.)

Note that the free end of each coupler 125/130 extends beyond the skin Sso that free end of each coupler is physically located outside of thepatient's body. Each coupler penetrates the skin S at a small incision(preferably a small “stab” wound) that surrounds the coupler. Thesegment of skin between each of the skin penetration sites of eachcoupler can be connected with a scalpel or other cutting instrument, sothat a single skin incision starts immediately inferior to the inferiorcoupler, extends between the couplers and ends immediately superior tothe superior coupler. If desired, the step of connecting the skinincision sites so as to form one larger incision may be performedearlier in the implantation procedure (such as, for example, at thestart of the procedure, wherein one larger incision is placed instead oftwo smaller ones. Alternatively, two small stab wounds may be used toadvance the guide wired 102 onto the bone. The incision may be thenenlarged after guide wire placement.)

The skin incision segment between the couplers is then extendedanteriorly from the level of the posterior skin incision, through thesoft tissues that are posterior to (i.e., in back of) the spinal columnuntil the posterior aspect of the vertebral bones are reached. That is,a corridor is developed between the couplers from the skin surface tothe posterior aspect of the vertebral bone, wherein, in a preferredembodiment, the corridor developed is similar to that of Corridor K,which is schematically shown in FIG. 4.

A distraction platform 180 is then attached onto each of the couplers125/130 (each coupler being attached to a screw assembly 105), whereinthe distraction platform is preferably, but not necessarily, adapted todistract the couplers towards or away from one another. An embodiment ofa distraction platform is shown positioned in FIG. 14. Distractionplatform 180 is an example of a platform that may be used and those ofordinary skill in the art will appreciate that any appropriatedistraction platform may be alternatively used in the illustratedmethod. (An example of a distractor platform is disclosed in U.S. Pat.No. 7,819,801. The text is included by reference in its entirety). Inthe preferred embodiment, the distractor has members adapted to interactwith the coupler 125/130 and at least one additional member adapted toretract soft tissues (such as muscle, fat and the like) away from thescrew 105/coupler 125/130 assemblies. A perspective view of the platformis shown in FIG. 15 A and multiple orthogonal views are shown in FIG.16. An exploded view is shown in FIG. 17 and section views are shown inFIGS. 18 and 19.

The distraction platform 180 has handle 182 and central body member 186that are interconnected by cylindrical region 181. Each of distractionarms 190 have an elongated member 192 that contains internal bore 1922,wherein bore 1922 extends the full length of the member 192. In apreferred embodiment, the internal bore 1922 of elongated member has aproximal (upper) opening 19226 and distal (lower) opening 19224, whereinthe proximal opening is smaller than the distal opening. A section viewthrough elongated members 192 is shown in FIG. 15B. Preferably, theexternal surface of elongated member 192 has markings that are labeledwith numbers, letters, or other designation. In use, bore 1922 containsthe proximal segment of coupler 125/130, wherein a segment of 1302 ofmember 130 emerges from the proximal (upper) opening 19226 of bore 1922.The smaller bore of opening 19226 permits segment 1302 of member 130 toexit bore 1922 but segment 1258 of member 125 is retained within member192 (see FIG. 15C). A locking nut 1107 can be used to engage thethreaded portion of segment 1302 that rests outside of member 192 and tolock the assembly of members 105, 125 and 130 relative to member 192 ofdistraction platform 180. When platform 180 engages couplers 125/130 andscrew assembly 105, the skin rests ator between markings of the externalsurface of elongated member 192. In this way, the distance from skin tothe bone fastener 105 can be easily read directly off of the externalmarkings of member 192.

Distraction arm 190 articulates with body 186. Arm 190 has slot 1902that is adapted to accept threaded post 1862 (threads not shown). Thumbwheel 194 has internal threads that threadedly interacted with threadedpost 1862 and produce a compressive force onto the end of arm 190 thatcontains slot 1902. With advancement of wheel 194, the segment ofdistraction arm 190 that contains slot 1902 is urged towards body 186,and the segment of distraction arm 190 that contains member 192 isrotated outwardly and away from body 186. After platform 180 is attachedto couplers 125/130 and screw assembly 105, thumb wheel(s) 194 may beactuated to impose a distractive force onto one or the other of thevertebral bones (or both). In this way, the vertebral bones may be movedaway from one another in the vertical plane. Bony distraction may beperformed before or after facet resection (or not at all). In apreferred embodiment, no distraction is performed prior to facetresection. In another preferred embodiment, distraction is performedprior to facet resection.

Arm 196 has side serrations 198. An end of arm 196 rests within bore1869 of body 186. A spring-loaded (spring not shown) pawl 1907 andmember 199 interact with serrations 198 of arm and serve as a mechanismto move arm into and out of bore 1869 of body 186. A removable tissueretractor 202 rests at the distal end of arm 196. Arm 202 has at leastone distal extension 2029 that interact with the retracted tissue.

A close-up view of the proximal end of removable tissue distraction armis shown in FIG. 20. Tissue distraction arm 202 has a protrusion 2022with surface 2024 that contains partial threads (adapted to interactwith threads of screw 2026). Protrusion 2022 rests within cut-out 1962of arm 196. A threaded screw 2026 resides within bore 1966 of arm 196. Aclip member 198 is adapted to rest within each of an upper channel 20264and lower channel 20266 that rest on each side of the threads of screw2026. The clip members 198 function to retain threaded screw 2026 withinbore 1966. Screw 2026 has a hex-shaped cut out 20262 that is adapted toaccept a complementary hex-drive screw driver.

As noted, distraction arm 202 is preferably removable in that the armcan be removed from cut-out 1962 of arm 196 by the surgeon at the timeof surgery. Rotation of screw 2026 (through the action of a hex-drivepositioned within cutout 20262) within bore 1966 will necessarilyproduce the interaction and movement of the threads of screw 2026 andthe threads of surface 2024 of arm 202. Rotation of screw 2026 in afirst direction will cause upward movement of arm 202, whereas rotationof screw 2026 in the opposite direction will produce downward movementof arm 202. With continued rotation of screw 2026 in one direction, thesurgeon can produce sufficient movement of arm 202 such that protrusion2022 exits cut-out 1962 of arm 196 and distraction arm 202 detaches fromdistraction platform 180. In this way, arm 202 is reversibly detachable(and mountable) relative to platform 180.

In the preferred embodiment, screw 2026 can be used to adjust thedistance from arm 196 to protrusions 2029 of distraction arm 202. Thisis an important and notable feature of the preferred distractionplatform. That is, in the preferred embodiment, distraction arm 202 isreversibly removable from distraction platform 180 and, when attached tothe platform, the vertical distance from a horizontal surface of member196 of platform 180 to the distal end (protrusions 2029) of arm 202 thatengage the soft tissues may be varied by the operating surgeon. (Whilethe variation in distance from platform 180 to protrusions 2029 of arm202 may be accomplished by the movement of an end of a fixed length arm202 relative to the platform, as illustrated, it may be alternativelyaccomplished my attachment of a variable length distraction arm 202which is stationary relative to the platform 180 at the point of mutualattachment).

Distraction arm 202 functions to retract muscle segment M1 (FIG. 4)medially towards spinous process SP and uncover the posterior aspect ofthe facet joint to be resected. After muscle retraction by arm 202,corridor K is expanded medially from that shown in Figure toapproximately that represented by the schematic drawing of FIG. 25B. Inthe preferred embodiment, the distraction platform 180 is coupled to thecoupler 125/130 and bone screw as shown in FIG. 14.

The surgeon may elect to use locking nuts 1107 to rigidly lock one ormore of the couplers 125/130 to platform 180. In addition, the platform180 may be further immobilized relative to the spine and the patient byapplying an articulated frame, wherein the frame is adapted to rigidlycouple to platform 180 on a first end and to rigidly attach to theoperating table at a second end. The frame further contains multiplesegments that are adapted to reversibly transition from a first state,wherein there are relative movements between the segments, to a secondstate, wherein the segments are rigidly affixed to each other. Finally,the surgeon may elect not to lock the frame to the couplers or to theoperating table.

Frame devices that anchor surgical retractors to the operating table arewell known in the art. In the illustrated device (FIG. 25D), articulatedframe 905 has member 9052 that reversibly attaches to the operatingtable onto which the patient is positioned. Member 9056 is adapted toreversibly and rigidly clamp onto a segment of platform 180. An end ofmember 9056 is adapted to clamp onto, for example, cylindrical segment181 of platform 180, wherein locking member 9058 locks end segment 9056after the latter is positioned onto segment 181. Member 9054 is adaptedto reversibly transition the frame 905 from the first state (movablyarticulating frame segments) to the second state (articulated framesegments are rigidly locked to one another). While an example of anarticulated frame 905 is illustrated, it is understood that any otherapplicable such device may be alternatively used. (For example, U.S.Pat. No. 4,254,763, U.S. Pat. No. 5,908,382, U.S. Pat. No. 6,302,843,U.S. Pat. No. 6,709,389, U.S. Pat. No. 7,156,806 and many other areknown to disclose surgical retractor systems that anchor to theoperating table. Each citation is hereby incorporated by reference inits entirety.)

In use, the distal tip of the tissue distraction must rest immediatelyposterior to the facet joint that will be resected. In selection of theproper distraction arm 202 to attach to the platform 180, the surgeonwill need to know the distance from the skin edge of the incision to theposterior aspect of the facet joint. This distance can be measureddirectly with a ruler. Alternatively, the distance from the skin edge tothe top of screw assembly 105 can be read directly off of the externalsurface markings of elongated member 192. In most patients, the distanceform the skin edge to the posterior aspect of the facet joint is closeto the distance from skin edge to the top of screw assembly 105 (of theinferior vertebral bone). The distance between the skin edge to the topof screw assembly 105 can be used a convenient approximation to thedistance from skin to the posterior aspect of the facet joint. Sincedistraction arm 202 is movable relative to arm 196, any differencebetween the distance from skin edge to the top of screw assembly 105 andthe distance from the skin edge to the posterior aspect of the facetjoint can be easily corrected by the movement of distraction arm 202relative to member 196 after attachment. However, if a distractionplatform is used wherein the distraction arm is stationary relative tothe attachment region of the platform, then the distance from skin tothe posterior aspect of the facet joint is preferably measured directlywith a ruler.

With the appropriate length tissue distraction arm 202 selected andpositioned within the incision between each of the fastener couplermembers—as shown in FIG. 23, a lateral X-ray is obtained. The distal endof the tissue distraction arm 202 is moved anterior/posteriorly byrotating screw 2026 until the distal end of arm 202 rests immediately inback of (i.e., posterior to) the facet joint 814 as shown in FIG. 24.The tissue distraction arm is moved medially by the rotation of member199 and arm 202 retracts muscle segment M1 towards the spinous processesSP of the superior and inferior vertebral bones (FIG. 25A). In this way,a working corridor WC is formed between each of the coupler engagementmembers and tissue distraction arm of the distraction platform, whereinthe posterior surface of the facet joint 814 is exposed and accessiblewithin working corridor WC.

The working corridor is seen in a different perspective in FIG. 25B.Note that the distraction arm 202 rests in proximity to the spinousprocess and permits access, through the working channel, to the facetjoint as well as the lamina portion of the vertebral bones. FIG. 25Cillustrates an approximation of the soft tissue corridor K (first shownin FIG. 4) after placement of the distraction platform the medicalretraction of distraction arm 202. (Note that corridor K isapproximately equivalent to the working corridor WC. For clarity ofillustration, the contents of the torso in FIG. 25C are representedchematically and those skilled in the art will appreciate that an actualcross section of the human torso may include anatomical details notshown in the illustration.)

After exposure of the facet joint, bone removing instruments are used tocut at least a segment of facet joint 814 and reveal the posterioraspect of the disc space that is immediately anterior to it. Preferably,there moved portion of the facet joint would include the lateral surfaceof the facet joint. The exposed portion of the disc space includes thesegment of the posterior disc surface that rests immediately anterior tothe neural foramen of the nerve root that exits the spinal canal beneaththe pedicle portion of the superior vertebral hone. That is, at least aportion of the exposed posterior disc surface rests, in thesuperior/inferior plane, between the inferior aspect of the nerve rootthat exits the spinal canal beneath the pedicle of the superiorvertebral bone and the superior aspect of the pedicle of the inferiorvertebral bone of the targeted PSI). The exposed portion of the discspace is bordered medially by the lateral aspect of the nerve root thatexits the spinal canal beneath the pedicle of the inferior vertebralbone of the targeted FSU.

While any instrument that is adapted to remove a portion of the facetjoint may be used, the removal is preferably made with one or moreinstruments that collectively drill away a portion of the bone androngeur away other joint fragments. In an embodiment, an instrument thatis adapted toper form both the drill and rongeur function is shown inFIGS. 26 to 30. It is understood that the illustrated instrument is notrestrictive in any way and any other instrument or combination ofinstruments that may remove bone by drilling and cutting the joint maybe alternatively used.

Instrument 260 is shown in multiple orthogonal views in FIG. 27 and inoblique views in FIG. 26. An exploded view is shown in FIG. 28. Sectionviews are shown in FIGS. 29 and 30. A section view of the device atabout plane N is shown in FIG. 29B, wherein a close-up view of thesection is shown in FIG. 29C.

A main body 262 has a foot segment 264. While not shown, the footsegment preferably has a sharpened edge about at least a portion of thecircumference, wherein the sharpened edge is adapted to cut bone. Amovable elongated member 280 has protrusions 282 that are adapted toengage members 296. Member 280 has cut outs 2802 adapted to engage edge2622 of member 262 so that member 280 can move along the long axis ofbody member 262. The distal end of member 280 is adapted to forciblyabut the foot segment 264 of body 262, wherein the distal end of member280 preferably has a sharpened circumferential edge that is adapted tocut bone.

In the assembled device, a central channel 272 is formed between member262 and 280. A movable handle member 301 is attached to body member 262using member 296 as shown in the illustrations. Cut out 2962 of member296 is adapted to engage protrusions 282 of member 280. In use, forciblehand actuation of the handle 301 towards the handle portion 2625 of body262 produces movement of member 280 relative to body 262 and advancesthe sharpened distal end of member 280 towards the sharpened footsegment 264. In this way, the intervening bone is cut and instrument 260functions like a rongeur. Spring members 305 are adapted to return thehandle 301 to the pre-actuation position (i.e., the position shown inFIG. 30) after the pressure placed by the surgeon's hand on member 301has been released.

FIG. 31 shows instrument 260 positioned to be advanced through workingcorridor WC while FIG. 32 shown the instrument fully advanced onto thefacet joint 814. Foot segment 264 of instrument 260 is passed lateral tojoint 814 and then moved medially so that the foot segment restsimmediately anterior to facet joint 814 (that is, the foot segment 264resets within the neural foramina of the exiting nerve). The sharpeneddistal end of member 280 rests posterior to facet joint 814. In thisway, the facet joint is positioned between each of foot 264 and distalaspect of member 280 of instrument 260. This is shown in FIG. 33. Adrill bit is placed through the central channel 272 of instrument 260and the facet joint 814 is drilled away until the free end of the drillbit abuts foot member 264. After drilling the facet joint, only a smallrim of bone is left between foot 264 and distal aspect of member 280.Hand actuation of handle 301 then cleaves the residual rim of bone. Thebone defect 321 formed by instrument 260 is shown in FIG. 34, with theinstrument 260 partially removed.

After removal of instrument 260, the surgeon may further removeadditional segments of the facet joint with burr, drill, bone rongeur,and the like. If desired, the spinal canal may be also decompressedthrough the working corridor WC. Removal of at least a portion of thelamina of the superior vertebral bone and at least a portion of thelamina of the inferior vertebral bone permits access to the spinal canaland decompression of both sides of the dural sac and nerve elements.This is schematically shown in FIG. 35, wherein the dural sac (DS) andcontained nerve elements are shown decompressed on the posterior andlateral aspects. (For clarity of illustration, the contents of FIG. 35are represented schematically and those skilled in the art willappreciate that an actual cross section of the human torso may includeanatomical details not shown in the illustration.)

After resection of the fact joint, the working corridor WC providesdirect access to the posterior aspect of the disc space. The posteriordisc space is accessed through a trans-foraminal corridor that extends,in the superior/inferior direction, between the nerve root that exitsthe spinal canal beneath the pedicle of the superior vertebral bone (L4vertebra in the illustration) and the pedicle of the inferior vertebralbone (L5 vertebra in the illustration). If vertebral fusion is desired,then at least partial removal of the disc material is performed and asegment of the bony endplate of each of the inferior surface of thesuperior vertebral bone (L4) and superior surface of the inferiorvertebral bone (L5) is striped of cartilage material and thendecorticated. Preparation of the disc space is well known in the art andwill not be described further.

If vertebral fusion is desired, then bone forming material is positionedinto the evacuated portion of the disc space. Preferably, but notnecessarily, an implant is concurrently implanted into the disc spacethat can bear at least some of the load transmitted across the discspace and maintain the superior and inferior vertebral bones separatedby a desired distance. While embodiments of disc space implants areshown, it is understood that any device adapted for implantation intothe disc space (including those adapted to produce vertebral fusion andthose intended to preserve vertebral motion, such as, for example, anartificial disc) may be used.

An embodiment of a disc implant 505 is shown in FIGS. 36A-37. The deviceis preferably curvilinear. The implant may be solid, as shown in FIGS.36A-36B, or it may contain a cavity adapted to house bone graftmaterial, wherein the material is adapted to fuse with one or both ofthe vertebral bones. The implant may be made of allograft bone, PEEK, orany other material that is appropriate for human or animal implantation.Preferably, the implant has a curvature K with center line L. Further,the implant may contain at least one cavity 507 that permitscommunication from one side of the implant body to the other—as shown inFIG. 37. The cavity permits formation of a bony connection between afusion mass on one side of the implant body and a fusion mass on theother side of the implant body.

At implantation, the implant 505 is preferably positioned at the defectformed in the posterior aspect of the Annulus Fibrosis of the disc spaceduring disc preparation (see FIG. 38A.) The implant is then rotatedalong an arc that is centered at the implant's center line L (note thatcenter line L goes in and out of the page). Thus only a point is shownFIG. 38A by an implantation 32 instrument (implantation instrument isnot shown). The implant is advanced as shown in FIG. 38B until it restsin the position shown in FIG. 39. Bone graft material is then placedinto the disc space adjacent to the implant (see FIG. 39). The bonegraft material can be placed into the disc space after implant placement(through the space lateral to the implant) or the bone graft materialcan be placed before implant placement. Further, more than one implantmay be advanced into the disc space. FIGS. 40A and 40B illustrate twopotential embodiments of implant positioning, wherein the implants arepreferably, but not necessarily, placed through a single disc spaceentry point “X”) within the Annulus Fibrosis.

After implantation of the disc space, the distraction platform isremoved. If the surgeon elects to add a fusion mass between theipsilateral transverse processes of the superior and inferior vertebralhones, then the transverse process of each of the superior and inferiorvertebral bones is stripped of the attached muscle and decorticated. Acolumn of bone forming material is then positioned in contact with thetransverse process of each of the superior and inferior vertebral bones,wherein the bone forming material also spans the space between thetransverse processes. With time, a solid column of mineralized boneshould form between the two transverse processes and serve as the fusionmass.

An inter-connecting member (for example, a rod) is used to interconnecteach of the superior and inferior bone fasteners 105. A locking element116 of each bone fastener 105 is then deployed so that each of the bonefasteners is rigidly attached to the interconnecting member. In thisway, the fasteners and interconnecting rod member will rigidlyinterconnect the superior and inferior vertebral bones that abut theimplanted disc space and immobilize the FSU containing the target discspace. The sequence is schematically shown in FIGS. 41A-41B.

Additional immobilization may be produced by the implantation offasteners/interconnecting member into the contra-lateral vertebralpedicles (i.e., on the contra-lateral side of the vertebral midline). Afusion mass may be also positioned, if desired, between thecontra-lateral transverse processes of the superior and inferiorvertebral bones. Alternatively, or additionally, a spinous processfastener that is adapted to rigidly affix to the spinous process of eachof the superior and inferior vertebral bones and rigidly immobilize theFSU may be used as an additional fixation implant. Preferably, thespinous process fastener is placed through the same ipsilateral skinincision used to perform the disc space implantation of the TLIFapproach.

An embodiment of a spinous process device is shown being implanted inFIGS. 42A-42B. The illustrated implant is more fully disclosed in U.S.application Ser. No. 12/940,960, filed by Abdou, Nov. 5, 2010. Theapplication is hereby incorporated by reference in its entirety.

In some patients, the distance between the pedicles of the superior andinferior vertebral bones of an FSU may be small. Under thosecircumstances, the positioning of a bone anchor assembly 105 into thepedicles each of the superior and inferior vertebral bones maysignificantly limit the space of the working corridor WC. Thus, it iscontemplated that hone screw 107 may be used alone as a bone attachmentfor the distractor platform—without being attached to housing 110 or theother members of the bone anchor assembly 105.

For example, a bone screw 107 may be attached to a coupler and thenadvanced into the ipsilateral pedicle portion of at least one of thesuperior or inferior vertebral bones. As previously described with bonescrew assembly 105, a distractor platform is coupled to each of the twoscrews 107/coupler and a third retractor blade (preferably, a removabletissue distractor blade) is used to retract the soft tissues mediallyand expose the facet joint. The facet resection and disc implantation ispreferably preformed as previously described—but may be alternativelyperformed using any specific instruments and techniques that the surgeondesires. After disc space preparation and device implantation(previously described), the distractor platform and couplers areremoved. The bone screws 107 are left implanted into the pedicleportions of the vertebral bones. If desired, a bone forming material maybe used to interconnect the ipsilateral transverse processes of thevertebral bones that border the implanted disc space—as previouslydescribed. With time, a bone fusion mass will develop between thetransverse processes.

A housing 610 and other member of the complete bone screw assembly maybe attached to the bone screw 107 in order to reconstitute a bone screwassembly that can reversibly accept an interconnecting rod. Bone screwassemblies that permit reversible coupling of the housing member to thebone screw 107 are known in the art. U.S. Pat. No. 6,248,105, U.S. Pat.No. 6,371,957 and others disclose hone screw assemblies wherein thehousing and the bone screw 107 may be reversibly detached by the surgeonat the time of surgery. (Each citation is hereby incorporated byreference in its entirety.) These devices are designed to permitadvancement of the bone screw into bone without an attached housingmember. After the bone work is done (or at any time the surgeonchooses), the housing member may be attached to the bone screw so thatthe assembly is reconstituted and ready to accept an interconnectingrod. After attachment of a housing member to each screw 107, aninterconnecting rod and a locking feature (may be a locking screw/nut ora feature built into the housing) is used to lock the interconnectingrod within the bone screw assembly.

FIGS. 43A-43C briefly illustrate an example of a device adapted toperform the method. The assembly of coupler member 630 and screw 107 isshown in an exploded view in FIG. 43A and in the assembled view in FIG.43B. Sectional views are shown in FIG. 43C. Bone screw 107 has a head1074 and an internal bore 1076, wherein the internal bore has a threadedportion 1078. A hex-shaped receptacle 1079 resides within head 1074.Receptacle 1079 is adapted to accept a screw driver (with, for example,a hex-shaped tip). wherein the driver can deliver a rotational force toscrew 107 and drive the threaded shaft into bone.

Coupler member 630 has an elongated body with a proximal threadedsegment 6302. Member 630 has a central bore 6304 that extends therethrough from the top to the bottom surface of member 630. A hex-shapedprotrusion 6306 projects distally, wherein hex-shaped protrusion 6306 isadapted to snuggly rest within hex-shaped cut out 1079 of screw 107 suchthat rotation of member 630 produces rotation of screw 107. Anadditional hex-shaped protrusion 6308 is located at the top of member630 (i.e., proximal aspect of member 630).

Member 640 has an elongated body with a proximal head 6402 and distalthreads 6404. Head 6402 has an indentation (or protrusion) that isadopted to mate and interact a screw driver (not shown) withcomplimentary protrusion (or indentation), so that rotation of thedriver produces rotation of member 640. An internal bore 6409 extendsthroughout member 640 so that guide wire 102 (FIG. 10) may be passedfreely through member 640, entering at a distal end and exiting at aproximal end of 640. In use, threads 6404 are adapted to cooperativelymate with threaded portion 1078 of screw 107. In this way, the assemblyof coupler member 630 and screw 107 is rigidly held in the assembledstate by member 640 and the assembly is allowed to function as a unitarydevice.

At surgery, the assembly of member 630 and screw 107 is passed overguide wire 102 to indentation 811 of the targeted vertebral bone. Screw107 is advanced into bone by applying a rotational force to segment 6308of member 630. After advancement into bone, the assembly is attached tothe distraction platform as previously described. If desired, nut 1107mates with threads 6302 of member 130 and permits rigid fixation of theassembly onto the distractor platform. These steps are schematicallyshown in FIGS. 44A-44B.

After the bone work is done (or at any point of the surgeon's choosing),member 630 is detached from bone screw 107. Housing members 610 are thenattached to the bone screws 107. This is schematically shown in FIGS.45A-45B. The screw assemblies are then ready to accept aninterconnecting rod. The rod/locking screw may be then inserted and usedto interconnect the bone screw assemblies as previously described (seeFIGS. 41A-41B).

Note that this methods of use differs from the previously illustratedembodiment only in that the screw assembly 105 my be reversiblysubdivided at the time of surgery into the hone screw 107 and housingportion. That is, the screw assembly 105 need not be used as a unitarydevice throughout the procedure, but the screw 107 may be usedindependently for a first portion of the procedure and then coupled tothe housing for use as an assembly at a second portion of the operation.Further, it is understood that the preceding method of use may bealternatively employed in any patient group, regardless of the distancebetween the pedicles of the superior and inferior vertebral bones.

In a modification of the immediately previous method, assembly 630 andscrew 107 are left attached after disc space implantation. Instead, thecomplete 630/107 assembly is removed for the vertebral bone, leaving anevacuated bone screw hole. A separate bone screw assembly 105 (of anyapplicable design) is then advanced into the pedicles that have beenevacuated by the removed coupler member 630/screw 107 assembly. That is,in this method, member 630/screw 107 are used as a temporary distractionscrew and coupling platform for distractor 180. After completion of thedisc space implantation, the temporary distraction screw (consisting ofmember 630 and screw 107) is removed and a bone screw assembly 105 isadvanced into the evacuated pedicle portion of the vertebral bone. Theimplanted bone screw assemblies 105 may be then interconnected with arod—as previously described (see FIGS. 41A-41B). A flow chartsummarizing the disclosed methods is shown in FIG. 45C.

In an additional embodiment, threaded screw member 730 is used to anchora distraction platform to the pedicle portion of the vertebral bone.Screw 730 has a threaded portion 7310 and elongated body 7300 (FIGS. 47Aand 47B). Body 7300 has proximal threaded segment 7302. A hex-shapedprotrusion 7308 is located at the top of member 730 (i.e., proximalaspect of member 730). Member 730 has a central bore 7304 that extendsthere through from the top to the bottom surface so that guide wire 102(FIG. 10) may be passed freely through member 730.

As previously described, at least one guide wire 102 is radiographicallyguided into the pedicle portion of at least one vertebral bone. Member730 is passed over guide wire 102 (wire 102 traverses central bore 7304)and threaded portion 7310 is advanced into the pedicle portion of thevertebral—as shown in FIGS. 47A and 47B. Retractor platform 745 is shownin FIGS. 48A-48C. The retractor is known in the art and similarplatforms have been disclosed in U.S. Pat. No. 5,795,291, USpublications 2005/0021040, 2006/0149278, 2009/0171394 and others. (Eachcitation is hereby incorporated by reference in its entirety.) Any ofthese retraction platforms may be alternatively used.

The retractor platform 745 has at least two curvilinear blades 7452 and7453. Blade 7452 is rigidly connected to bar 7455, while blade 7453 ismovable along bar 7455. Thumb wheel 7458 is connected to a screw whichthreadedly engages threaded bore of blade 7453 (mechanism is not shown).In this way, rotation of thumb wheel 7458 produces translationalmovement of blade 7453 along bar 7455. Each blade contains at least onebore 7451, wherein the bore 7451 is adapted to accept member 730.

While briefly described above, it is understood that retractor 745 andsimilar retractor platforms are known in the art and have been disclosedin U.S. Pat. No. 5,795,291, US publications 2005/0021040, 2006/0149278,2009/0171394 and others. (Each citation is hereby incorporated byreference in its entirety.) Any applicable retractor platforms may bealternatively used to accomplish the illustrated method of exposing thefacet joint.

After advancement of threaded portion 7310 into the pedicle portion ofthe vertebral bone, the retractor 745 is advanced over member 730 to thecorrect position and coupled to the underling bone through member 730(see FIGS. 48B and 48C). A retractor 770 (FIG. 49) is used to retractthe muscle segment M1 medially towards the spinous process—as shown inFIG. 48B. Retractor 770 is similar to distractor 180 but lacks sideretractor members 190. That is, retractor 770 contains handle 182,central body member 186 and interconnecting cylindrical region 181. Arm196 rests within a cavity of central body 186 and is movable therein. Aspring-loaded (spring not shown) pawl 1907 and member 199 interact withserrations 198 of arm and serve as a mechanism to move arm into and outof bore 1869 of body 186. A removable tissue retractor 202 rests at thedistal end of arm 196. Arm 202 has at least one distal extension 2029that interact with the retracted tissue. A more full description of thedistractor is provided above.

Retractors 745 and 770 are preferably connected to a frame device thatanchors to the operating table (such as, for example that shown 25D).Preferably, the frame device attaches to segment 181 of retractor 770and to the region of bore 7459 of retractor platform 745. After theframe device is locked and made rigid, the attached retractor platforms745 and 770 are held in desired positions as shown in FIG. 48C. In thisway, a working corridor leading to the facet joint is created whereintwo of the retractor blades are connected to a retractor platform whichmay (or may not) be subsequently connected to a frame device that isattached to the operating table. The third retractor is independentlyattached to the frame device.

An alternative embodiment is shown in FIG. 50. In this embodiment, bothbar 7455 is a member of the frame device that is attached to theoperating room table. Each blade member 7453 may be guided to thepedicle by anchored member 730 and then reversibly mountable onto bar7455. (The blades may be radiographically guided to the pedicle positionwithout prior placement of member 730. In order to illustrate thisoption, a first blade 7453 is shown attached to screw 730 in FIG. 50while a second blade 7453 is not.) After moving the blade member intothe desired position relative to bar 7455, a locking mechanism (setscrew 792 here) is actuated to immobilize the blade member relative tobar 7455. As before, retractor platform 770 is also attached to theframe device. In this way, each of the three retractor blades that formand border the working corridor are independently attached to the framedevice that attaches to the operating table.

In an alternative embodiment, at least a first vertebral bone of thefirst and second vertebral bones that must be fused is radiographicallyidentified. A first facet joint is also radiographically identified,wherein the first facet joint forms an articulation between the firstand second vertebral bones. A marker is radiographically guided directlyinto the facet joint and the retractor platform is then advanced overthe marker to the facet joint. In the preferred embodiment, a firstthreaded segment of a first bone fastener is threadedly advanced intothe identified first facet joint under radiographic guidance prior toretractor platform placement. The anchored first bone fastener is usedto guide and position the retraction platform relative to the firstfacet joint

FIGS. 51A and 51B show placement of guide wire 102 directly into thefacet joint space between the IAP of the superior vertebral bone and SAPof the interior vertebral bone. (As in prior embodiments, this step isperformed under radiographic guidance and prior to direct surgicalexposure of the facet joint.) A screw member, such as, for example,member 730 (FIG. 46A-46B) is advanced over the guide wire 102 underradiographic visualization. Threaded segment 7310 is driven into thefacet joint so that the threads engage the IAP (superior vertebra)medially and the SAP (inferior vertebra) laterally (FIG. 51C).

Cylindrical tubes of progressively greater diameter are sequentiallypassed over member 730 in order to dilate the surrounding soft tissue(FIG. 52A). This method of serial advancement of cylindrical tubes iswell known to those of ordinary skill in the art. A retractor platform810 is then advanced over the cylindrical tubes—as shown in FIG. 52B.While the blades are configured differently, the retractor platform 810is similar to retractor 745 and description of the retractor will not berepeated. The semicircular tissue retraction retractor blades ofretractor 810 are preferably, but not necessarily, devoid of bore 7451.

After advancement of retractor platform 810, the cylindrical tubes andmember 730 are removed leaving a working corridor within the centralaspect of the semi-cylindrical retractor blades (FIG. 53A). The bladesmay be separated further by actuating thumb wheel 7458 in order toprovide a larger working corridor (FIG. 53B). If desired, the platform810 may be attached to a frame device (similar to FIG. 25D) that isanchored to the operating table. The frame device may attach to theregion of bore 7459 of retractor platform 810. FIG. 54 illustrates aschematic view down the working corridor. Note that the facet jointnecessarily rests at the bottom of the working corridor since placementof the retractor 810 was guided by member 730. That is, member 730 wasanchored to the facet joint as an initial step in the operation and theanchor was then used to define the trajectory of the surgical corridorto the facet joint. The positioned retraction platform 810 may befurther coupled to a frame device that anchors to the operating table(FIG. 25D).

After removal of member 730 and the cylindrical tubes, a surgicalcorridor is left between the tissue retractor blades through which theposterior aspect of the first facet may be accessed. The surgeonvisually identifies and verifies that the posterior aspect of the firstfacet joint is at the distal end of the surgical corridor. Any softtissue remaining over the posterior aspect of the facet joint isremoved. The facet joint is then at least partially removed as describedpreviously in detail. Preferably, at least a portion of the lateralsurface of the SAP of inferior vertebral bone is removed with facetjoint resection. The posterior aspect of the disc space that isimmediately anterior to resected facet joint (and neural foramen) isexposed. The disc space is entered and at least partially evacuated andan orthopedic implant is positioned within the disc space as discussedin detail above.

In specific, the exposed disc entered through a transforaminal corridor,wherein the entry point of the posterior disc is at least partially inbetween the nerve root that exits the spinal canal beneath the pedicleof the superior vertebral bone and the pedicle of the inferior vertebralbone and lateral to the nerve that exits immediately beneath the pedicleof the inferior vertebral bone. An orthopedic implant is positioned intothe disc space, wherein the implant can bear at least some of the loadtransmitted across the disc space and maintain the superior and inferiorvertebral bones separated by a desired distance. Bone forming materialis preferably positioned in the disc space if a fusion is desired. Theretraction platform is removed.

If desired, prior to retraction platform removal, an additional bonefusion mass may be used to connect the transverse processes adjacent toremoved facet joint—as discussed previously. In addition, a first bonescrew assembly is anchored into the first pedicle of the superiorvertebral bone and a second bone screw assembly is anchored into theipsilateral pedicle of the inferior vertebral bone. The hone screwassemblies are then rigidly interconnected by a rod member.

A modification of the previous embodiment is shown in FIG. 55. In thisembodiment, both bar 7455 is a member of the frame device that isattached to the operating room table. Each blade member 7453 may beguided to the facet joint by anchored member 730 (as shown in the lastembodiment) and then reversibly mounted onto bar 7455. (Further, theblades may be radiographically guided to the facet joint over guide wire102 and cylindrical tubes without threaded advancement of member 730into the facet joint. However, use of threaded member 730 provides lessmovement (and potential error) during retractor advancement). Aftermoving the blade member into the desired position relative to bar 7455,a locking mechanism (set screw 792 here) is actuated to immobilize theblade member relative to bar 7455. As before, retractor platform 770 isalso attached to the frame device. In this way, each of the tworetractor blades that form and border the working corridor areindependently attached to the frame device that anchors to the operatingtable.

The disclosed devices or any of their components can be made of anybiologically adaptable or compatible materials. Materials consideredacceptable for biological implantation are well known and include, butare not limited to, stainless steel, titanium, tantalum, combinationmetallic alloys, various plastics, resins, ceramics, biologicallyabsorbable materials and the like. Any components may be alsocoated/made with osteo-conductive (such as deminerized bone matrix,hydroxyapatite, and the like) and/or osteo-inductive (such asTransforming Growth Factor “TGF-B,” Platelet-Derived Growth Factor“PDGF,” Bone-Morphogenic Protein “BMP,” and the like) bio-activematerials that promote bone formation. Further, any surface may be madewith a porous ingrowth surface (such as titanium wire mesh,plasma-sprayed titanium, tantalum, porous CoCr, and the like), providedwith a bioactive coating, made using tantalum, and/or helical rosettecarbon nanotubes (or other carbon nanotube-based coating) in order topromote bone in-growth or establish a mineralized connection between thebone and the implant, and reduce the likelihood of implant loosening.Lastly, the system or any of its components can also be entirely orpartially made of a shape memory material or other deformable material.

While this specification contains many specifics, these should not beconstrued as limitations on the scope of what is claimed or of what maybe claimed, but rather as descriptions of features specific toparticular embodiments. Certain features that are described in thisspecification in the context of separate embodiments can also beimplemented in combination in a single embodiment. Conversely, variousfeatures that are described in the context of a single embodiment canalso be implemented in multiple embodiments separately or in anysuitable sub-combination. Moreover, although features may be describedabove as acting in certain combinations and even initially claimed assuch, one or more features from a claimed combination can in some casesbe excised from the combination, and the claimed combination may bedirected to a sub-combination or a variation of a sub-combination.Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. Only a few examples and implementations are disclosed.Variations, modifications and enhancements to the described examples andimplementations and other implementations may be made based on what isdisclosed.

What is claimed is: 1-23. (canceled)
 24. An orthopedic implant,comprising: a curvilinear body member comprising at least a firstipsilateral side surface and an opposing contra-lateral side surface;wherein said curvilinear body is configured to extend along acurvilinear trajectory having a center of rotation positionedipsilateral to said first ipsilateral side surface; wherein saidcurvilinear shape of said body member is such that said firstipsilateral side surface is substantially concave relative to saidcenter of rotation; and wherein said curvilinear body is configured tobe advanced into an intervertebral disc space of a subject via rotationthereof about a circular trajectory centered at said center of rotation.25. The implant of claim 24, wherein said curvilinear body furthercomprises at least one cavity.
 26. The implant of claim 25, wherein saidat least one cavity is configured to permit formation of a bonyconnection of a fusion mass on said first ipsilateral side of saidcurvilinear body and a fusion mass on said opposing contra-lateral sideof said curvilinear body.
 27. The implant of claim 24, wherein saidadvancement of said curvilinear body into said intervertebral disc spaceof said subject further comprises an interaction of said curvilinearbody with at least one implantation instrument.
 28. The implant of claim24, further comprising at least one interconnecting member configured toconnect at least two bone fasteners, each bone fastener rigidlyinterconnecting a respective superior and inferior vertebral bone, saidsuperior and inferior vertebral bones abutting said disc space.